Block 1, of mass m 1 = 4.70kg , moves along a frictionless air track with speed
ID: 1272387 • Letter: B
Question
Block 1, of mass m1 = 4.70kg , moves along a frictionless air track with speed v1 = 23.0m/s . It collides with block 2, of mass m2 = 41.0kg , which was initially at rest. The blocks stick together after the collision.(Figure 1) http://session.masteringphysics.com/problemAsset/1000172620/6/MLM_in_5.jpg
A: Find the magnitude pi of the total initial momentum of the two-block system.
B: Find the final velocity of the two blocks after they have stuck together.
C: What is the change ?K=Kfinal?Kinitial in the two-block system's kinetic energy due to the collision?
D: Is this collision elastic or inelastic?
Explanation / Answer
A) pi = m1*v1 + m2*v2....
pi = 4.7*23 + 41*0...
pi = 108.1 kg.m/sec...
B) v = m1*v1/(m1+m2) = (4.7*23)/(4.7+41) = 2.37 m/sec....
C) Kfinal- Kinitial = [(1/2)*(m1+m2)*V^2]-[(1/2)*m1*v1^2]..
delta K = -1115.3 J....
D) inelastic